Bruce Fordyce is an outstanding ultramarathoner. He won the legendary Comrades 90 km race in South Africa an incredible eight years in a row, 1981-88, and has set other long-distance records which still stand. In 1896 John Addison Fordyce, an American dermatologist and probably no relation to Bruce, described a subcutaneous phenomenon which now bears his name. As summarized by the New Zealand Dermatological Society:

Angiokeratomas are small dark red to purple raised spots. They may also have a rough scaly surface. They are composed of surface blood vessels (dilated capillaries). Often unnoticed, they may become crusty and bleed if accidentally scratched or damaged, or a harmless clot may form in the lesion (thrombosis), changing the colour to dark purple or black overnight.

The angiokeratoma of Fordyce is ugly but utterly benign. Online references make no mention of any connection to running, but I have observed a strong correlation in my own case, which otherwise seems quite typical. Fordyce's angiokeratoma most commonly occurs in a delicate male anatomical location. Sensible people (i.e., non-trail-runners) would be well advised not to research the topic any further. They definitely should avoid clicking on links and loading images that illustrate the affliction! As for its seriousness, Joseph J. Shaffer and Vincent de Leo note:

The importance of these lesions was well summarized by Bean, "These varicules should be known so that we can allay the fears of old men, many of whom have worries enough already."